So I've established that you can't exactly force a person to change with belief, but there's a different sort of exception I need to cover:  the creation of new people.
	Let's say there is a city with some societal problems, and that they start blaming the mole men for it.  The mole men weren't real, of course; it's just a scapegoat.  But it's a successful scapegoat, and eventually it's a common belief in the city.  Well, now mole men really do exist.  They can exist now either as illusions or half-men.
	Illusions appear to be real until scrutinized, at which point their existence will sort of implode due to contradictions.  There's not much else to say about illusions, so I'll carry the example with half-men.  Half-men are like empty shells of men, and the empty parts organically fill over time.  Half-men can ultimately become able to generate CE fields.
	While this process can be used to create monsters, that's not what's happening in this example.  The belief is that the mole men are like men, but with twisted motives and unusual traits that allow them to flourish under the surface.  While not coordinated, there will be some coherency in the general belief of how mole men live and why they keep sabotaging crops or whatever nonsense.  Things will, of course, become worse for that city as their scapegoats get out of hand.  Because it's become such a culural fixture for the city, though, it may be impossible to destroy the mole men - really depends on the details of all the beliefs.
	But the mole men still exist with enough human traits to undergo natural progression through human invention.  If they weren't believed to have a society, they'll probably invent it anyway.  Given enough time, they'll have language, art, and tools.  Now, this is most likely a disaster for this city, but with enough political will there could be negotiation and symbiosis.  The only way for the organic evolution of these mole men to stop is total genocide.  If that doesn't occur, they'll eventually be internally robust enough to have complex beliefs and CE fields.  Once they gain the protection of CE fields, they gain the ability to contradict the beliefs they were imprinted with, also.
	I should take a moment to point out that human psychology is absolutely necessary for these mechanics to function.  If the mole men were just mindless monsters, they'd never really evolve.  Similarly, if they held some incomprehensible alien psychology, they'd never really evolve.  I'm basically categorizing life into three groups:  human (even if not literally homo sapien), sub-human (like beasts and insects), and alien (like an eldritch abomination).  Only the human group gets to generate the chaos of chimerical equity.
	For your easy baked-in metaphor, there's a period of time there where the mole men can be manipulated by the city simply from them changing their beliefs about them, which are rooted in a refusal to accept responsibility (which would require some sort of cultural revalation or revolution).  Metaphors make easy plots, and all that.
	Now, that was the creation of believers.  It can't be done directly, but it can be done.  Next, there's an easier thing that can be created:  observers.  An observer doesn't necessarily have its own CE field, but it can have an echoed boost towards the belief of people observing those observers.
	Example:  say I believe that grass is razor sharp, and that I'm enough of a hermit to make it happen with conviction.  If a dog walks on that grass and cuts up its paws on it, that's a direct affirmation of my belief.  The dog was an observer - it observed the reality.  Now, this is just normal psychology, but when a person has their beliefs affirmed by outside evidence, those beliefs become stronger.  We can then say that having more observers leads to stronger beliefs.
	That's simple enough to see, but there aren't always gonna be convenient observers like that.  Observers can be created, though.  It should be plain enough to understand how a half-man like the mole men can count towards observation.  But illusions can perform this task as well.  The illusions can also be entirely internal and mundanely psychological.
	If I create a mental model that's really robust, like an imaginary friend, they can count as an observer easily because it's easy to get mental models to affirm your beliefs.  A mental model isn't going to be as convincing as a real living observer, but it's enough for a little extra conviction.
	To see it become a useful process, you just need a more elaborate example:  say I believe I can shoot lasers from my eyes.  Now say I have 100 squirrels paralyzed and forced to watch a specific location.  I go to the location get a huge boost of affirmation if I successfully perform the feat (or rather, if I believe I convinced the squirrels...), and now I have really strong eye lasers.  [there are systems in place to prevent this from happening on a large scale, but the explanation will have to wait for a future section]